package 比赛.赛氪.test;

import java.util.Scanner;

public class test3 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        float sum = 0;
        int index = 5;
        while (index-- > 0)
            sum += in.nextInt();
        System.out.println(String.format("%.1f",sum/5));
    }
}
